Information processing device, communication system, and information processing method

ABSTRACT

Reception of a frame is appropriately stopped. 
     A communication system is a communication system that includes first and second information processing devices. The first information processing device performs control such that a signal (which is a signal having backward compatibility) serving as an index by which the second information processing device receiving a frame stops the reception of the frame is transmitted to the second information processing device. The second information processing device performs control such that the reception of the frame is stopped based on the signal (which is a signal having backward compatibility) serving as an index by which reception of the frame is stopped when the frame transmitted from the first information processing device is received.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.16/775,284, filed Jan. 29, 2020, which is a continuation of U.S.application Ser. No. 15/315,014, filed Nov. 30, 2016 (now U.S. Pat. No.10,582,423), which is based on PCT filing PCT/JP2015/065747, filed Jun.1, 2015, which claims priority to JP 2014-142951, filed Jul. 11, 2014,the entire contents of each are incorporated herein by reference.

TECHNICAL FIELD

The present technology relates to an information processing device.Particularly, the present technology relates to an informationprocessing device, a communication system, and an information processingmethod of exchanging information using wireless communication.

BACKGROUND ART

In the related art, there are wireless communication technologies forexchanging information using wireless communication. For example,communication methods of exchanging information between informationprocessing devices using wireless LANs have been proposed.

In this way, when wireless communication is performed, error detectionmethods of detecting whether there are errors in data of received framesusing frame check sequences (FCSs) have been proposed. When errors aredetected in received frames in accordance with error detection methods,the frames are discarded. Conversely, when errors are not detected inreceived frames, media access control (MAC) headers are read todetermine whether the frames are destined for own information processingdevices. When the frames are not destined for the own informationprocessing devices, the received frames are discarded despite the factthat content of the frames are correct.

In the error detection methods, it is necessary to demodulate up to allthe last ends of the frames in addition to the MAC headers and comparechecksums generated from values of the demodulated frames to the FCSs.Therefore, after the frames are received to the last, it is determinedthat there are errors in the data. Therefore, for example, when thereare errors in time points of the MAC headers or when frames are notdestined for own information processing devices despite the fact thatthere are no errors in the time points of the MAC headers, thisdetermination may not be performed before the frames are all received.

Accordingly, for example, wireless packet communication systems in whichfields for storing error detection codes for headers of packets arenewly provided at the ends of the headers of the packets for protocolsof upper layers of the physical layers have been proposed (for example,see Patent Literature 1).

CITATION LIST Patent Literature

-   Patent Literature 1: JP 2000-261462A

DISCLOSURE OF INVENTION Technical Problem

In the technologies of the related art described above, address andcontrol information in headers is inspected by protocols of higherlayers of the physical layer. When it is confirmed that the headers areinvalid, when it is confirmed that the address and control informationis valid according to error detection codes and there are no addressesdestined for own information processing devices, or when controlinformation is not control information which can be received by owninformation processing devices, an instruction to stop the reception istransmitted to the physical layer.

However, in the technologies of the related art described above, thereis a concern that wireless communication devices which are not capableof recognizing the fields newly provided to store the error detectioncodes may not correctly demodulate received frames. Accordingly, it isimportant to appropriately stop receiving the frames which are beingreceived in consideration of backward compatibility.

It is desirable to provide the present technology for appropriatelystopping reception of a frame.

Solution to Problem

The present technology has been made to solve the above problem. A firstaspect of the present technology is an information processing method, aprogram causing a computer to execute the method, and an informationprocessing device including a control unit configured to perform controlin a manner that a signal having backward compatibility and serving asan index by which another information processing device receiving aframe stops the reception of the frame is transmitted to the otherinformation processing device. Thus, it is possible to obtain anoperational effect in which the signal (which is a signal havingbackward compatibility) serving as the index by which anotherinformation processing device receiving the frame stops the reception ofthe frame is transmitted to the other information processing device.

According to the first aspect, the control unit may use, as the index,information which is based on a calculation result obtained using a MACheader. Thus, it is possible to obtain an operational effect in whichthe information which is based on the calculation result obtained usinga MAC header is used as the index.

According to the first aspect, the control unit may store theinformation which is based on the calculation result in a header of aphysical layer in the frame and uses the information as the signal.Thus, it is possible to obtain an operational effect in which theinformation which is based on the calculation result is stored in aheader of a physical layer in the frame and is used as the signal.

According to the first aspect, the control unit may use, as the index,one frame among a plurality of frames in a connection frame in which theplurality of frames are connected. Thus, it is possible to obtain anoperational effect in which one frame among the plurality of frames inthe connection frame is used as the index.

According to the first aspect, the control unit may store, as an index,an address of a transmission source or an address of a transmissiondestination as information which is the index, in a header of a physicallayer in the frame. Thus, it is possible to obtain an operational effectin which the address of the transmission source or the address of thetransmission destination as information which is the index is stored asan index in the header of the physical layer in the frame.

According to the first aspect, the control unit may determine whether totransmit the signal based on at least one of information from a basestation, information from a wireless slave station, a length of atransmission target frame, and whether to perform transmission in abundle of a plurality of frequencies. Thus, it is possible to obtain anoperational effect in which whether to transmit the signal is determinedbased on at least one of information from a base station, informationfrom a wireless slave station, a length of a transmission target frame,and whether to perform transmission in a bundle of a plurality offrequencies.

A second aspect of the present technology is an information processingmethod, a program causing a computer to execute the method, and aninformation processing device including a control unit configured toperform control in a manner that reception of a frame transmitted fromanother information processing device is stopped based on an index bywhich reception of the frame is stopped and which is specified by asignal having backward compatibility when the frame is received. Thus,it is possible to obtain an operational effect in which the reception ofthe frame transmitted from another information processing device isstopped based on the index (which is an index specified by the signalhaving backward compatibility) by which reception of the frame isstopped when the frame is received.

According to the second aspect, the index may include an FCS of a MACheader included in the signal, and the control unit may determinewhether there is an error in data of the MAC header based on acomparison result between the FCS and a checksum calculated based on theMAC header. Thus, it is possible to obtain an operational effect inwhich whether there is an error in data of the MAC header is determinedbased on a comparison result between the FCS and a checksum calculatedbased on the MAC header.

According to the second aspect, the index may be stored in one frameamong a plurality of frames in a connection frame in which the pluralityof frames are connected. Thus, it is possible to obtain an operationaleffect in which the index is stored in one frame among the plurality offrames in the connection frame.

According to the second aspect, the index may be stored in a header of aphysical layer. Thus, it is possible to obtain an operational effect inwhich the index is stored in the header of the physical layer.

According to the second aspect, the control unit may determine whetherthere is an error in data of a MAC header of the frame based on theindex and performs control in a manner that the reception of the frameis stopped when there is the error in the data of the MAC header. Thus,it is possible to obtain an operational effect in which whether there isan error in data of a MAC header of the frame is determined based on theindex, and control is performed such that the reception of the frame isstopped when there is the error in the data of the MAC header.

According to the second aspect, when there is no error in data of a MACheader of the frame, the control unit may determine that the receptionof the frame is stopped in a case in which the frame is transmitted in aunicast manner and a transmission destination of the frame is notdestined for the own information processing device and a case in whichthe frame is transmitted in a multicast manner and the transmissiondestination of the frame is not destined for a multicast group to whichthe own information processing device belongs. Thus, it is possible toobtain an operational effect in which when there is no error in data ofthe MAC header, it is determined that the reception of the frame isstopped in the case in which the frame is transmitted in the unicastmanner and the transmission destination of the frame is not destined forthe own information processing device and the case in which the frame istransmitted in the multicast manner and the transmission destination ofthe frame is not destined for the multicast group to which the owninformation processing device belongs.

According to the second aspect, when there is no error in data of a MACheader of the frame, the control unit may determine that the receptionof the frame is stopped in a case in which the frame is transmitted in abroadcast manner and a transmission destination of the frame is not aninformation processing device to which the own information processingdevice is connected. Thus, it is possible to obtain an operationaleffect in which when there is no error in data of the MAC header, it isdetermined that the reception of the frame is stopped in the case inwhich the frame is transmitted in the broadcast manner and thetransmission destination of the frame is not the information processingdevice to which the own information processing device is connected.

According to the second aspect, when there is no error in data of a MACheader of the frame, the control unit may perform control in a mannerthat a carrier sense level is changed in a case in which a transmissiondestination or a transmission source of the frame of which the receptionis stopped is not an information processing device to which the owninformation processing device is connected. Thus, it is possible toobtain an operational effect in which when there is no error in data ofthe MAC header, control is performed such that the carrier sense levelis changed in the case in which the transmission destination or thetransmission source of the frame of which the reception is stopped isnot the information processing device to which the own informationprocessing device is connected.

According to the second aspect, the control unit may perform control ina manner that transmission suppression is set until a reception endtiming of the frame of which the reception is stopped. Thus, it ispossible to obtain an operational effect in which the transmissionsuppression is set until the reception end timing of the frame of whichthe reception is stopped.

According to the second aspect, when the transmission suppression isset, the control unit may perform control in a manner that anacknowledgement is transmitted in a case in which a frame destined forthe own information processing device is received, at least one frameamong frames destined for the own information processing device iscorrectly receivable, and it is necessary to transmit theacknowledgement to a transmission source of the frame destined for theown information processing device. Thus, it is possible to obtain anoperational effect in which when the transmission suppression is set,the acknowledgement is transmitted in the case in which the framedestined for the own information processing device is received, at leastone frame among frames destined for the own information processingdevice is correctly receivable, and it is necessary to transmit theacknowledgement to the transmission source of the frame destined for theown information processing device.

According to the second aspect, when there is no error in data of a MACheader of the frame, the control unit may perform control in a mannerthat the transmission suppression is set during a transmissionsuppression period decided based on information stored in the frame ofwhich the reception is stopped. Thus, it is possible to obtain anoperational effect in which when there is no error in the data of theMAC header, the transmission suppression is set during a transmissionsuppression period decided based on information stored in the frame bywhich the reception is stopped.

A first aspect of the present technology is an information processingmethod, a program causing a computer to execute the method, and acommunication system including: a first information processing deviceconfigured to perform control in a manner that a signal having backwardcompatibility and serving as an index by which a second informationprocessing device receiving a frame stops the reception of the frame istransmitted to the second information processing device; and the secondinformation processing device configured to perform control in a mannerthat the reception of the frame is stopped based on the signal when theframe transmitted from the first information processing device isreceived. Thus, it is possible to obtain an operational effect in whichthe first information processing device performs transmits the signal(which is a signal having backward compatibility) serving as the indexby which the second information processing device receiving the framestops the reception of the frame to the second information processingdevice, and the second information processing device stops the receptionof the frame based on the signal when the frame transmitted from thefirst information processing device is received.

Advantageous Effects of Invention

According to the present technology, it is possible to obtain the goodadvantageous effects in which reception of frames can be appropriatelystopped. Note that the advantageous effects described above are notnecessarily limitative, and the advantageous effects described in thepresent disclosure may be achieved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a system configuration example of acommunication system 10 according to a first embodiment of the presenttechnology.

FIG. 2 is a block diagram illustrating an internal configuration exampleof an information processing device 100 according to the firstembodiment of the present technology.

FIG. 3 is a diagram illustrating a configuration example of a MAC frameformat of IEEE 802.11 which is a basis of the present technology.

FIG. 4 is a diagram schematically illustrating an example of a receptiontiming of a frame which is a basis of the present technology.

FIG. 5 is a diagram illustrating a configuration example of a PLCPheader exchanged between information processing devices included in thecommunication system 10 according to the first embodiment of the presenttechnology.

FIG. 6 is a flowchart illustrating an example of a processing procedureof a frame transmission process by the information processing device 100according to the first embodiment of the present technology.

FIG. 7 is a flowchart illustrating an example of a processing procedureof a frame reception process by the information processing device 200according to the first embodiment of the present technology.

FIG. 8 is a flowchart illustrating a process of determining whether totransmit a reception stop signal in the frame transmission process bythe information processing device 100 according to the first embodimentof the present technology.

FIG. 9 is a flowchart illustrating a process of determining whether totransmit a reception stop signal in the frame transmission process bythe information processing device 200 according to the first embodimentof the present technology.

FIG. 10 is a flowchart illustrating a transmission determination processfor a reception stop signal in the frame transmission process by theinformation processing device 100 according to the first embodiment ofthe present technology.

FIG. 11 is a flowchart illustrating a reception stop determinationprocess in the frame reception process by the information processingdevice 200 according to the first embodiment of the present technology.

FIG. 12 is a flowchart illustrating a frame reception stop process inthe frame reception process by the information processing device 200according to the first embodiment of the present technology.

FIG. 13 is a diagram illustrating a configuration example of a frameformat of an A-MPDU exchanged between information processing devicesincluded in a communication system 10 according to a second embodimentof the present technology.

FIG. 14 is a flowchart illustrating a reception stop determinationprocess in the frame reception process by the information processingdevice 200 according to the second embodiment of the present technology.

FIG. 15 is a flowchart illustrating a frame reception stop process inthe frame reception process by the information processing device 200according to the second embodiment of the present technology.

FIG. 16 is a flowchart illustrating a process of determining whether totransmit a reception stop signal in the frame transmission process bythe information processing device 100 according to a third embodiment ofthe present technology.

FIG. 17 is diagram illustrating a configuration example of HE-SIG-Aexchanged between information processing devices included in acommunication system 10 according to a third embodiment of the presenttechnology.

FIG. 18 is a flowchart illustrating a transmission determination processfor a reception stop signal in a frame transmission process by theinformation processing device 100 according to the third embodiment ofthe present technology.

FIG. 19 is a flowchart illustrating a reception stop determinationprocess in the frame reception process by the information processingdevice 200 according to the third embodiment of the present technology.

FIG. 20 is a flowchart illustrating a frame reception stop process inthe frame reception process by the information processing device 200according to the third embodiment of the present technology.

FIG. 21 is a block diagram showing an example of a schematicconfiguration of a smartphone.

FIG. 22 is a block diagram showing an example of a schematicconfiguration of a car navigation apparatus.

FIG. 23 is a block diagram showing an example of a schematicconfiguration of a wireless access point.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, modes for carrying out the present technology (hereinafterreferred to as embodiments) will be described. The description will bemade in the following order.

1. First embodiment (example in which information serving as index forstopping reception is stored in SERVICE of PLCP header)

2. Second embodiment (example in which head frame of A-MPDU is set asreception stop signal)

3. Third embodiment (example in which reception stop signal is generatedusing SIG (HE-SIG-A) for IEEE 802.11ax).

4. Application examples

1. First Embodiment

[Configuration Example of Communication System]

FIG. 1 is a diagram illustrating a system configuration example of acommunication system 10 according to a first embodiment of the presenttechnology.

The communication system 10 includes an information processing device100 and information processing devices 200 to 204. The informationprocessing device 100 is an example of the first information processingdevice described in the claims. The information processing devices 200to 204 are examples of the information processing device described inthe claims.

The information processing device 100 is an information processingdevice which is a center of a wireless network. Here, as a communicationscheme, a communication scheme in conformity with, for example, awireless local area network (LAN) standard of Institute of Electricaland Electronic Engineers (IEEE) 802.11 can be used. As the wireless LAN,for example, Wireless Fidelity (Wi-Fi), Wi-Fi Direct, or Wi-Fi CERTIFIEDMiracast specification (technical specification name: Wi-Fi Display) canbe used. Wireless communication using another communication scheme maybe performed.

For example, the information processing device 100 is realized by anaccess point or a base station that is connected to each informationprocessing device using a wireless LAN and exchanges each piece ofinformation. For example, the information processing device 100 may beconnected to an external network such as the Internet in a wired orwireless line.

The information processing devices 200 to 204 are information processingdevices that are wirelessly connected to the information processingdevice 100. In FIG. 1 , a connection relation between the informationprocessing device 100 and the information processing devices 200 to 204is illustrated schematically by dotted lines. For example, when awireless LAN is used as a communication scheme, the informationprocessing devices 200 to 204 corresponds to stations.

For example, the information processing device 100 can be set as a fixedinformation processing device that has a wireless communicationfunction. The information processing devices 200 to 204 can set as, forexample, portable information processing devices that have wirelesscommunication functions.

Here, the portable information processing devices are, for example,information processing devices such as smartphones, mobile phones, ortable terminals. The fixed information processing device is, forexample, an information processing device such as a base station, anaccess point, a printer, a personal computer, or a home appliance.

In the first embodiment of the present technology, an example in whichbroadcast transfer, unicast transfer, or multicast transfer is performedin the communication system 10 will be described. Here, the broadcasttransfer is a transfer scheme of transmitting data to unspecified manyinformation processing devices in a network. That is, the broadcasttransfer is a transfer scheme of transmitting data to neighboringinformation processing devices without deciding destinations. Theunicast transfer is a transfer scheme of designating one informationprocessing device and transmitting data to the information processingdevice in a network. The multicast transfer is a transfer scheme ofdesignating a plurality of information processing devices andtransmitting data to these information processing devices in a network.For example, in the multicast transfer, data can be simultaneouslytransmitted to information processing devices in a group.

[Configuration Example of Information Processing Device]

FIG. 2 is a block diagram illustrating an internal configuration exampleof the information processing device 100 according to the firstembodiment of the present technology. The internal configurations of theinformation processing devices 200 to 204 are substantially the same asthat of the information processing device 100. Therefore, only theinformation processing device 100 will be described and the otherdevices will not be described.

The information processing device 100 includes an antenna 110, acommunication unit 120, a control unit 130, and a storage unit 140.

The communication unit 120 is a unit (for example, a wireless LAN modem)that transmits and receives radio waves via the antenna 110. Thecommunication unit 120 is assumed to perform wireless communication inconformity to at least one of the above-described communication schemes.

The control unit 130 controls each unit of the information processingdevice 100 based on a control program. For example, the control unit 130performs signal processing on transmitted and received information. Forexample, the control unit 130 is realized by a central processing unit(CPU).

For example, when the communication unit 120 transmits data using awireless communication, the control unit 130 processes transmissiontarget information and generates a chunk of data to be actuallytransmitted (transmission packets). Subsequently, the control unit 130outputs the generated transmission packets to the communication unit120. The communication unit 120 converts the transmission packets intopackets with a format of a communication scheme for actual transfer, andsubsequently transmits the converted transmission packets from theantenna 110 to the outside.

For example, when the communication unit 120 receives data using thewireless communication, the communication unit 120 extracts receptionpackets through signal processing performed on a radio wave signalreceived via the antenna 110 by a receiver of the communication unit120. Then, the control unit 130 interprets the extracted receptionpackets. When it is determined that the reception packets are data to bemaintained as the interpretation result, the control unit 130 recordsthe data on the storage unit 140.

For example, the control unit 130 performs control such that a signal(which is a signal having backward compatibility) serving as an index bywhich each of other information processing devices (for example, theinformation processing devices 200 to 204) receiving a frame stops thereception of the frame is transmitted to each of the other informationprocessing devices. In this case, the control unit 130 can useinformation which is based on a calculation result obtained using amedia access control (MAC) header (for example, a frame check sequence(FCS) of up to the MAC header) as the index. Here, for example, a framecheck sequence (FCS) of up to the MAC header can be used as theinformation which is based on the calculation result. The control unit130 can store the information which is based on the calculation resultin the header of the physical layer in the frame and use the informationas a signal serving as the index by which the reception of the frame isstopped. Here, the header of the physical layer is, for example, aphysical layer convergence procedure (PLCP) header.

For example, when a frame transmitted from the information processingdevice 100 is received, a control unit (corresponding to the controlunit 130) of the information processing device 200 performs control suchthat the reception of the frame is stopped. For example, the controlunit of the information processing device 200 can perform control suchthat the reception of the frame is stopped based on an index (an index((for example, the FCC of up to the MAC address) specified by a signalhaving backward compatibility) by which the reception of the frame isstopped.

The storage unit 140 has a role of a working area for data processing bythe control unit 130 or a function of a storage medium that retainsvarious kinds of data. As the storage unit 140, for example, a storagemedium such as a nonvolatile memory, a magnetic disk, an optical disc,or a magneto-optical (MO) disc can be used. As the nonvolatile memory,for example, an electrically erasable programmable read-only memory(EEPROM) or an erasable programmable ROM (EPROM) can be used. As themagnetic disk, for example, a hard disk or a disk-shaped magnetic disccan be used. As the optical disc, for example, a compact disc (CD), adigital versatile disc recordable (DVD-R), or a Blu-ray disc (BD(registered trademark)) can be used.

Here, as described above, there is an error detection method ofdetecting whether there is an error in data of a received frame in awireless LAN. For example, there is known an error detection method inwhich a transmitter stores a checksum of transmitted data as a bitstring called a frame check sequence (FCS) in a frame in advance.According to the error detection method, a receiver can detect an errorby comparing a checksum generated from received data to a value of theFCS.

For example, when a value of a checksum generated from a received frameis different from a value of the FCS, an information processing devicereceiving the frame determines that there is an error in the receivedframe and discards the frame.

Conversely, when the value of the checksum generated from the receivedframe is the same as the value of the FCS, the information processingdevice receiving the frame determines that there is no error in thereceived frame. Then, the information processing device reads a mediaaccess control (MAC) header.

Here, a MAC address of a transmission source, a MAC address of atransmission destination, and a transmission suppression time are storedin the MAC header. The MAC address of the transmission source isreferred to as a transmission address (TA). The MAC address of thetransmission destination is referred to as a received address (RA). Thetransmission suppression time is referred to as a network allocationvector (NAV).

For example, when an RA of a received frame is different from a MACaddress of the own information processing device, the informationprocessing device discards the received frame despite the fact thatcontent of the received frames are correct. In this way, the informationprocessing device discarding the fame does not perform transmission inthe NAV.

Conversely, the information processing device which determines thatthere is no error in the received frame and of which the MAC address ofthe own information processing device is identical to the RA sends apayload of the MAC to an upper layer.

In this way, when the error detection is performed, it can be determinedwhether data is destined for the own information processing device,using information in the MAC header.

[Example of MAC Frame Format]

FIG. 3 is a diagram illustrating a configuration example of a MAC frameformat of IEEE 802.11 which is a basis of the present technology. TheMAC frame format is configured to have a MAC header 301, a frame body302, and an FCS 303.

Here, a case in which the MAC frame format of IEEE 802.11 is used toperform error detection is assumed. In this case, for the MAC frameformat of IEEE 802.11 illustrated in FIG. 3 , it is necessary todemodulate up to all the last end of a frame in addition to the MACheader 301 and to compare a checksum generated from values of thedemodulated frame to the FCS. In order to determine whether there is anerror in data, the frame has to be received to the last.

For this reason, for example, when an error is detected at the timepoint of the MAC header or when no error is detected but a frame is nota frame destined for the own information processing device, thisdetermination may not be performed before the frame is all received.

“Example of Reception Timing of Frame”

FIG. 4 is a diagram schematically illustrating an example of a receptiontiming of a frame which is a basis of the present technology. In FIG. 4, the horizontal axis represents a time axis. In FIG. 4 , receptiontimings of two frames 21 and 22 are compared to each other in thedescription.

As illustrated in FIG. 4 , a case in which the information processingdevice receives the frame 21 is assumed. For example, the RA of theframe 21 is different from the MAC address of the own informationprocessing device. Therefore, the frame 21 is assumed to be a packetwhich is discarded even when the frame 21 is normally receivable.

The information processing device which is receiving the frame 21 maynot determine whether the frame 21 is a frame destined for the owninformation processing device before the last end of the frame 21 isreceived.

In such a situation, the frame 22 destined for the own informationprocessing device is assumed to arrive before the frame 21 is completelyreceived. In this case, the information processing device which isreceiving the frame 21 may not switch the frame 21 to the frame 22 tostart the reception. Therefore, after the reception of the frame 21 iscompleted and it is determined that the frame 21 is not a frame destinedfor the own information processing device (a position indicated by anarrow 23), the frame 22 has already arrived halfway and is in anunreceivable state.

In this way, there is a concern of reception of a frame destined for theown information processing device not being started and a receptionopportunity being missed even when a frame destined for the owninformation processing device newly arrives during reception of a framewhich is not destined for the own information processing device or inwhich there is an error.

Accordingly, in an embodiment of the present technology, an example inwhich error detection for a frame (for example, a MAC header) isperformed without changing the format of the frame will be described.Thus, it is possible to appropriately determine whether to stopreception of a frame which is being received and improve a receptionopportunity of a frame.

[Configuration Example of PLCP Header]

FIG. 5 is a diagram illustrating a configuration example of a PLCPheader exchanged between information processing devices included in thecommunication system 10 according to the first embodiment of the presenttechnology.

The PLCP header means the header of a physical layer. FIG. 5 illustratesthe PLCP header in conformity to the IEEE 802.11 specification. The PLCPheader is configured to include RATE 311, Reserved 312, LENGTH 313,Parity 314, Tail 315, and SERVICE 316.

SERVICE 316 is prepared as a field that is used to synchronize adescrambler of a receiver. In the IEEE 802.11 specification, there is anunused RESERVE region which is merely reserved. An informationprocessing device which does not correspond to a function of stoppingreception of a frame does not use data described in the RESERVE region.Therefore, an information processing device which does not correspond tothe function of stopping reception of a frame can perform a normalreception process without using the function.

Accordingly, in the first embodiment of the present technology, bydescribing information serving as an index by which reception is stoppedin the RESERVE region, it is possible to ensure backward compatibility.

That is, the control unit 130 of the information processing device 100calculates an FCS of up to a MAC header as the information serving asthe index by which reception is stopped and stores the calculated FCS inthe RESERVE region of the field of SERVICE 316 included in the PLCPheader.

Similarly, in the information processing devices 200 to 204, an FCS ofup to a MAC header can be stored as a signal serving as the index bywhich reception is stopped in the RESERVE region of the field of SERVICE316 included in the PLCP header.

Here, the function of stopping reception of a frame is assumed to mean afunction according to each of the first to third embodiments of thepresent technology. A reception stop signal is assumed to mean a signalserving as an index by which reception is stopped.

[Operation Example of Transmission-Side Information Processing Device]

FIG. 6 is a flowchart illustrating an example of a processing procedureof a frame transmission process by the information processing device 100according to the first embodiment of the present technology. In FIG. 6 ,a case in which the information processing device 100 is a transmissionside information processing device will be described as an example.

First, a process of determining whether to transmit a reception stopsignal is performed (step S720). The process of determining whether totransmit a reception stop signal will be described in detail withreference to FIG. 8 .

Subsequently, the control unit 130 determines whether transmission ofthe reception stop signal is possible, as a result of the process ofdetermining whether to transmit the reception stop signal (S701). Whenthe transmission of the reception stop signal is not possible (stepS701), the control unit 130 transmits a frame without storing theinformation (for example, the FCS of up to the MAC header) serving asthe index by which the reception is stopped (step S702).

When the transmission of the reception stop signal is possible (stepS701), a transmission determination process for the reception stopsignal is performed (step S740). The transmission determination processfor the reception stop signal will be described in detail with referenceto FIG. 10 .

Subsequently, the control unit 130 transmits a frame which stores theinformation serving as the index by which reception is stopped or aframe which does not store the information serving as the index by whichreception is stopped (step S702). Steps S701, S702, S720, and S740 arean example of a transmission procedure described in the claims.

[Operation Example of Reception-Side Information Processing Device]

FIG. 7 is a flowchart illustrating an example of a processing procedureof a frame reception process by the information processing device 200according to the first embodiment of the present technology. In FIG. 7 ,a case in which the information processing device 200 is areception-side information processing device will be described as anexample.

First, a reception stop determination process is performed (step S750).The reception stop determination process will be described in detailwith reference to FIG. 11 .

Subsequently, a control unit (corresponding to the control unit 130illustrated in FIG. 2 ) of the information processing device 200determines whether reception of a frame which is being received isstopped, as a result of the reception stop determination process (stepS711). When the reception of the frame which is being received isstopped (step S711), a frame reception stop process is performed (stepS760). The frame reception stop process will be described in detail withreference to FIG. 12 .

When the reception of the frame which is being received is not stopped(step S711), the reception of the frame is continued (step S712).

[Operation Example of Process of Determining Whether to TransmitReception Stop Signal]

FIG. 8 is a flowchart illustrating the process of determining whether totransmit the reception stop signal (the processing procedure of stepS720 illustrated in FIG. 6 ) in the frame transmission process by theinformation processing device 100 according to the first embodiment ofthe present technology.

The process of determining whether to transmit the reception stop signalis a process generated when the information processing device 100transmitting the reception stop signal (which is a signal serving as theindex by which reception is stopped) receives a predetermined signalfrom another information processing device. Whether transmission of thereception stop signal is possible is determined based on at least onepiece of information between an Association Request frame and a ProbeRequest frame and element information regarding the informationprocessing device 100.

The control unit 130 determines whether at least one of the AssociationRequest frame and the Probe Request frame is received (step S721). Suchframes are transmitted from other information processing devices (forexample, the information processing devices 200 to 204).

The Association Request frame is a frame used when other informationprocessing devices (for example, the information processing devices 200to 204) establish connection to the information processing device 100.The Probe Request frame is a frame used when other informationprocessing devices (for example, the information processing devices 200to 204) scan the information processing device 100.

When neither the Association Request frame nor Probe Request frame isreceived (step S721), monitoring is continued.

When at least one of the Association Request frame and the Probe Requestframe is received (step S721), the control unit 130 confirms elementinformation of a received frame. The element information of the framestores information indicating whether the reception of the receptionstop signal is possible.

Information indicating whether the transmission of the reception stopsignal is possible means, for example, information by which it can bespecified whether the information processing device is an informationprocessing device corresponding to IEEE 802.11ax. When the informationprocessing device is an information processing device corresponding toIEEE 802.11ax, it can be determined that the information processingdevice is an information processing device corresponding to receptionstop (an information processing device capable of receiving thereception stop signal).

The control unit 130 determines whether a transmission source of thereceived frame is the information processing device corresponding toreception stop (step S722). When the transmission source of the receivedframe is the information processing device corresponding to receptionstop (step S722), the control unit 130 confirms the element informationregarding the own information processing device. Then, based on theinformation indicating whether the transmission of the reception stopsignal is possible in the element information regarding the owninformation processing device, the control unit 130 determines whetherthe transmission of the reception stop signal is possible (step S723).That is, the control unit 130 determines whether the own informationprocessing device (the information processing device 100) is aninformation processing device (an information processing device capableof transmitting the reception stop signal) corresponding to receptionstop.

Here, the information indicating whether the transmission of thereception stop signal is possible means, for example, information bywhich it can be specified whether the information processing device isan information processing device corresponding to IEEE 802.11ax.

When the own information processing device (the information processingdevice 100) is the information processing device corresponding toreception stop (step S723), the control unit 130 determines that thetransmission of the reception stop signal is possible (step S724). Thatis, when the own information processing device (the informationprocessing device 100) can transmit the reception stop signal and thetransmission source of the frame can receive the reception stop signal,the control unit 130 determines that the transmission of the receptionstop signal is possible.

When the own information processing device (the information processingdevice 100) is an information processing device which does notcorrespond to reception stop (step S723), the control unit 130determines that the transmission of the reception stop signal is notpossible (step S726).

When the transmission source of the received frame is an informationprocessing device which does not correspond to reception stop (stepS722), the control unit 130 confirms the other information processingdevices already connected to the information processing device 100 (theinformation processing device of the connection destination). Then, thecontrol unit 130 determines whether there are one or more informationprocessing devices corresponding to reception stop among informationprocessing devices of a connection destination (step S725).

When there is one or more information processing devices correspondingto reception stop among the information processing devices of theconnection destination (step S725), the process proceeds to step S724.Conversely, when there is none of the information processing devicecorresponding to reception stop among the information processing devicesof the connection destination (step S725), the process proceeds to stepS726.

FIG. 9 is a flowchart illustrating a process of determining whether totransmit a reception stop signal (the processing procedure of step S720illustrated in FIG. 6 ) in the frame transmission process by theinformation processing device 200 according to the first embodiment ofthe present technology.

FIG. 9 illustrates an example of the process of determining whether totransmit the reception stop signal when the information processingdevice 200 is a transmission-side information processing device. Theprocess of determining whether to transmit the reception stop signal issubstantially the same as that when the information processing device100 is a transmission-side information processing device, but isdifferent in a type of frame used when use or non-use is determined.

That is, the information processing device 200 determines whether totransmit the reception stop signal based on at least one piece ofinformation between a Beacon frame and a Probe Response frame and theelement information of the information processing device 200. FIG. 9illustrates an example in which the Beacon frame and the Probe Responseframe are transmitted from the information processing device 100.

Here, the Beacon frame is a frame used when the information processingdevice 100 reports information regarding the own information processingdevice. The Probe Response is a response to a Probe Request transmittedby the information processing device 200 and means a frame storing eachpiece of information regarding the information processing device 100.

The control unit 130 determines whether at least one of the Beacon frameand the Probe Response frame is received (step S731). Each of the framesis transmitted from the information processing device 100.

When neither the Beacon frame nor the Probe Response frame is received(step S731), monitoring is continued. When at least one of the Beaconframe and the Probe Response frame is received (step S731), the processproceeds to step S732. Subsequent processes (steps S732 to S736)correspond to processes (steps S722 to S726) illustrated in FIG. 8 .Therefore, the description thereof will be omitted here.

[Operation Example of Transmission Determination Process for ReceptionStop Signal]

FIG. 10 is a flowchart illustrating a transmission determination processfor a reception stop signal (the processing procedure of step S740illustrated in FIG. 6 ) in the frame transmission process by theinformation processing device 100 according to the first embodiment ofthe present technology.

Based on the length of a transmission target frame, the control unit 130determines whether the reception stop signal is transmitted (step S741).For example, based on the length of an aggregation frame, the controlunit 130 determines whether the reception stop signal is transmitted(step S741). In this case, the control unit 130 determines whether thelength of the aggregation frame is equal to or greater than a threshold(step S741).

Here, aggregation is a technology for bundling a plurality of frames andtransmitting the bundle of frames as one frame. Aggregation frames meana plurality of frames which are bundled to be transmitted as one frame.In other words, aggregation frames are a plurality of frames which areconnected to be transmitted as one frame.

For example, when a short frame has a length less than the threshold, atime in which the frame is interpreted is assumed to be short althoughthe entire frame is interpreted. Accordingly, in the first embodiment ofthe present technology, when the length of the frame is equal to orgreater than the threshold, the reception stop signal is transmitted.

For example, a standard used to determine whether a type of frame is adata frame may be set as a standard used to determine whether thereception stop signal is transmitted. For example, when a type of frameis a management frame or a control frame, a case in which transmissionto a destination with which connection is not completed is performed isconsidered. In this case, the reception stop signal is not transmittedin order not to stop the frame on a reception side. In contrast, when atype of frame is a data frame, the reception stop signal is transmitted.

When the length of the aggregation frame is less than the threshold(step S741), the control unit 130 determines that the reception stopsignal is not transmitted (step S744).

When the length of the aggregation frame is equal to or greater than thethreshold (step S741), the control unit 130 determines whether thereception stop signal is transmitted based on whether channel bonding isused for the transmission (step S742).

Here, the channel bonding is a technology for performing transmission ina bundle of a plurality of channels. When a plurality of channels areused, it is assumed that many communication resources are used. However,when one channel (or a small number of channels) is used, it is assumedthat many communication resources are not used. Accordingly, in thefirst embodiment of the present technology, the reception stop signal istransmitted when the channel bonding is used for the transmission.

When the channel bonding is used for the transmission (step S742), thecontrol unit 130 determines that the reception stop signal istransmitted (step S743). In this case, the control unit 130 storesinformation (an FCS of up to a MAC header) serving as the index by whichreception is stopped in a frame and transmits the frame in which theinformation serving as the index is stored (step S743). Specifically,the control unit 130 stores the information (for example, the FCS of upto the MAC header) serving as the index by which reception is stopped inthe RESERVE region of SERVICE 316 illustrated in FIG. 5 .

When the channel bonding is not used for the transmission (step S742),the control unit 130 determines that the reception stop signal is nottransmitted (step S744). In this case, the control unit 130 transmitsthe frame without storing the information serving as the index by whichreception is stopped (step S744).

In this way, the control unit 130 can determine whether to transmit thesignal serving as the index by which the reception is stopped based onat least one of the length of the transmission target frame and whetherto perform the transmission in a bundle of a plurality of frequencies.The control unit 130 can determine whether to transmit the signalserving as the index by which the reception is stopped based on at leastone of information from a base station and information from a wirelessslave station. The control unit 130 can determine whether to transmitthe signal serving as the index by which the reception is stopped basedon at least one of the pieces of information.

[Operation Example of Reception Stop Determination Process]

FIG. 11 is a flowchart illustrating the reception stop determinationprocess (the processing procedure of step S750 illustrated in FIG. 7 )in the frame reception process by the information processing device 200according to the first embodiment of the present technology.

The information processing device 200 receives a frame transmitted fromthe information processing device 100. In this way, when the receptionof up to the MAC header in the frame transmitted from the informationprocessing device 100 is completed, the control unit of the informationprocessing device 200 confirms the FCS of the MAC header stored in theService field of the PLCP header. The FCS is stored in, for example, theRESERVE region of SERVICE 316 illustrated in FIG. 5 .

Then, the control unit of the information processing device 200determines whether a checksum calculated from the received MAC header isidentical to a value of the FCS of the MAC header (step S751). When thechecksum is not identical to the value (step S751), the control unit ofthe information processing device 200 determines that there is an errorin the frame and determines that the reception of the frame is stopped(step S758). Thus, the reception of the frame is stopped (step S758).

When the checksum is identical to the value (step S751), the controlunit of the information processing device 200 determines whether thereceived frame is a frame transmitted in a unicast manner (step S752).

When the received frame is the frame transmitted in the unicast manner(step S752), the control unit of the information processing device 200confirms the RA (the MAC address of a transmission destination) storedin the MAC header (step S753). When the RA is the address of the owninformation processing device (step S753), the control unit of theinformation processing device 200 performs control such that thereception of the frame is continued (step S754).

Conversely, when the RA is not the address of the own informationprocessing device (step S753), the control unit of the informationprocessing device 200 determines that the frame is not a frame destinedfor the own information processing device and determines that thereception of the frame is stopped (step S758). Thus, the reception ofthe frame is stopped and the frame is discarded (step S758).

When the received frame is not the frame transmitted in the unicastmanner (step S752), the control unit of the information processingdevice 200 confirms the TA (the MAC address of the transmission source)stored in the MAC header (step S755). When the TA is the address of anAP (the information processing device 100) which is the connectiondestination (step S755), the control unit of the information processingdevice 200 determines whether the received frame is a frame transmittedin a broadcast manner (step S756).

When the received frame is the frame transmitted in the broadcast manner(step S756), the control unit of the information processing device 200performs control such that the reception of the frame is continued (stepS754).

When the TA is not the address of an AP (the information processingdevice 100) which is the connection destination (step S755), the controlunit of the information processing device 200 determines that the frameis not the frame from the AP (the information processing device 100)which is the connection destination and determines that the reception ofthe frame is stopped (step S758). Thus, the reception of the frame isstopped and the frame is discarded (step S758).

When the received frame is not the frame transmitted in the broadcastmanner (step S756), the control unit of the information processingdevice 200 confirms the RA (the MAC address of the transmissiondestination) stored in the MAC header (step S757). Then, when the RA isthe address of a group to which the own information processing devicebelongs (step S757), the control unit of the information processingdevice 200 performs control such that the reception of the frame iscontinued (step S754).

When the RA is not the address of the group to which the own informationprocessing device belongs (step S757), the control unit of theinformation processing device 200 determines that the frame is not theframe to the group to which the own information processing devicebelongs and determines that the reception of the frame is stopped (stepS758). Thus, the reception of the frame is stopped and the frame isdiscarded (step S758).

In this way, the control unit of the information processing device 200can determine whether there is an error in data of the MAC header in theframe based on the index (the FCS of up to the MAC header) by which thereception of the frame is stopped. Specifically, the control unit of theinformation processing device 200 determines whether there is an errorin the data of the MAC header based on a comparison result between theFCS of the MAC header and the checksum calculated based on the MACheader. Then, when there is the error in the data of the MAC header, thecontrol unit of the information processing device 200 performs controlsuch that the reception of the frame is stopped.

When there is no error in the data of the MAC header, the control unitof the information processing device 200 can determine whether thereception of the frame is stopped based on whether the frame istransmitted in the unicast manner and whether the transmissiondestination of the frame is destined for the own information processingdevice. Specifically, when the frame is transmitted in the unicastmanner and the transmission destination of the frame is not destined forthe own information processing device, the control unit of theinformation processing device 200 determines that the reception of theframe is stopped.

When there is no error in the data of the MAC header, the control unitof the information processing device 200 can determine whether thereception is stopped based on whether the frame is transmitted in thebroadcast manner and whether the transmission destination of the frameis the connection destination of the own information processing device.Specifically, when the frame is transmitted in the broadcast manner andthe transmission destination of the frame is not the connectiondestination of the own information processing device, the control unitof the information processing device 200 determines that the receptionof the frame is stopped.

[Operation Example of Frame Reception Stop Process]

FIG. 12 is a flowchart illustrating the frame reception stop process(the processing procedure of step S760 illustrated in FIG. 7 ) in theframe reception process by the information processing device 200according to the first embodiment of the present technology.

First, the control unit of the information processing device 200determines whether the checksum calculated from the received MAC headeris identical to the value of the FCS of the MAC header stored in thePLCP header (step S761). When the checksum is identical to the value(step S761), the control unit of the information processing device 200calculates an end time of the received frame based on LENGTH and RATEstored in the PLCP header (step S762). LENGTH stored in the PLCP headercorresponds to LENGTH 313 illustrated in FIG. 5 and RATE corresponds toRATE 311 illustrated in FIG. 5 . When the checksum is identical to thevalue, a transmission suppression time (NAV) can be acquired.

Then, the control unit of the information processing device 200 setstransmission suppression so that transmission is not performed for a sumtime of the transmission suppression time (NAV) stored in the MAC headerand the calculated end time of the received frame (step S762).

By doing so, it is possible to reduce unnecessary transmission. Theinformation processing device 200 can reduce power and can also improvea system throughput by reducing collision occasions of frames.

Subsequently, the control unit of the information processing device 200confirms the RA (the MAC address of the transmission destination) andthe TA (the MAC address of the transmission source) stored in the MACheader (step S763). Then, it is determined whether the TA or the RA isthe address of an AP (other than the information processing device 200)other than the connection destination (step S763).

When the TA or the RA is the address of the AP (other than theinformation processing device 100) other than the connection destination(step S763), the transmission suppression is cancelled and the value ofa CCA threshold is increased to perform transmission. Therefore, thecontrol unit of the information processing device 200 changes thecarrier sense level (step S764). For example, when a default value ofthe carrier sense level is −82 dBm, the carrier sense level is changedfrom −82 dBm to −62 dBm. This change is an example and the carrier senselevel may be changed to another value.

Here, the CCA threshold is a threshold used when channel access isperformed and a channel is determined to be in an idle state. When thethreshold is increased, a plurality of information processing devices(slave stations) can simultaneously perform transmission. Therefore, itis possible to increase a system throughput.

Subsequently, the control unit of the information processing device 200determines whether it is during a DSC (step S765). Here, the DSC means achange period of the carrier sense level. When it is not during the DSC(step S765), the control unit of the information processing device 200performs setting so that the carrier sense level returns to the default(step S770).

When it is during the DSC (step S765), the control unit of theinformation processing device 200 receives a new frame during the DSCand determines whether the frame is a frame for which it is necessary totransmit an acknowledge (step S766). That is, the control unit of theinformation processing device 200 receives a new frame during the DSCand does not detect an error using the FCS at the end of the frame, andthen determines whether the frame is destined for the own informationprocessing device and it is necessary to transmit an acknowledge for theframe (step S766).

When a new frame is received during the DSC and the frame is a frame forwhich it is necessary to transmit an acknowledgement (step S766), thecontrol unit of the information processing device 200 transmits theacknowledgement to the transmission source of the frame (step S769).

Similarly, the control unit of the information processing device 200receives a new aggregation frame during the DSC and does not detect anerror using the FCS at the end of at least one frame, and thendetermines whether the frame is destined for the own informationprocessing device and it is necessary to transmit a block acknowledge(step S766). When a new aggregation frame is received during the DSC andthe aggregation frame is a frame for which it is necessary to transmit ablock acknowledgement (step S766), the block acknowledgement istransmitted to the transmission source of the frame (step S769).

When a new frame is not received during the DSC or a received frame isnot a frame for which it is necessary to transmit an acknowledgement(step S766), the control unit of the information processing device 200determines whether there is data to be transmitted (step S767). Whenthere is no data to be transmitted (step S767), the process returns tostep S765.

When there is the data to be transmitted (step S767), the datatransmission process by the DSC starts (step S768) and the processreturns to step S765.

When the checksum calculated from the received MAC header is notidentical to the value of the FCS of the MAC header stored in the PLCPheader (step S761), the control unit of the information processingdevice 200 calculates an end time of the received frame (step S771). Asdescribed above, the control unit of the information processing device200 calculates the end time of the received frame based on LENGTH andRATE stored in the PLCP header. Since the control unit of theinformation processing device 200 may not read the transmissionsuppression time (NAV) stored in the MAC header, the control unit of theinformation processing device 200 may not specify the transmissionsuppression time (NAV).

Then, the control unit of the information processing device 200 setstransmission suppression so that transmission is not performed until thecalculated end time of the received frame (step S771).

Subsequently, the control unit of the information processing device 200determines whether a period is a transmission suppression period (stepS772). When the period is not the transmission suppression period (stepS772), the control unit of the information processing device 200 cancelsthe transmission suppression (step S775).

When the period is the transmission suppression period (step S772), thecontrol unit of the information processing device 200 receives a newframe and determines whether the frame is a frame for which it isnecessary to transmit an acknowledgement (step S773).

Then, when the control unit of the information processing device 200receives the new frame and the frame is the frame for which it isnecessary to transmit the acknowledgement (S773), the control unit ofthe information processing device 200 transmits the acknowledgement tothe transmission source of the frame (step S774). These processes (stepsS773 and S774) correspond to the above-described processes (steps S766and S769). Therefore, the description thereof will be omitted here.

In this way, when there is no error in the data of the MAC header, thecontrol unit of the information processing device 200 performs controlsuch that the transmission suppression is set for a sum period of aperiod until a reception end timing of a frame of which reception isstopped and the transmission suppression period stored in the frame.

When there is no error in the data of the MAC header and thetransmission destination or the transmission source of the frame ofwhich the reception is stopped is not a connection destination of theown information processing device, the control unit of the informationprocessing device 200 performs control such that the carrier sense levelis changed.

When there is an error in the data of the MAC header, the control unitof the information processing device 200 stops the reception of theframe and performs control such that the transmission suppression is setuntil a reception end timing of the frame.

When the transmission suppression is set and a predetermined conditionis satisfied, the control unit of the information processing device 200performs control such that an acknowledgement is transmitted. Here, thepredetermined condition is a case in which frames destined for the owninformation processing device are received, at least one frame of theframes destined for the own information processing device is correctlyreceivable, and it is necessary to transmit an acknowledgement to thetransmission source of the frames destined for the own informationprocessing device.

In this way, according to the first embodiment of the presenttechnology, it is possible to appropriately stop receiving a frame ofwhich the reception starts in consideration of backward compatibility.

2. Second Embodiment

In a second embodiment of the present technology, an example in which anaggregated MAC protocol data unit (A-MPDU) frame serves as a receptionstop signal will be described. Specifically, a MAC payload of a headsubframe of the A-MPDU frame is set to 0 and the head subframe serves asa reception stop signal. That is, a frame (where the MAC payload is 0)formed by only a MAC header and an FCS is transmitted as a receptionstop signal.

The configuration of an information processing device according to thesecond embodiment of the present technology is substantially the same asthe information processing devices 100 and 200 to 204 illustrated inFIG. 1 and the like. Therefore, the same reference numerals as those ofthe first embodiment of the present technology are given to portionscommon to the first embodiment of the present technology, and thedescription thereof will be omitted partially.

Some of the processes in the second embodiment of the present technologyare common to those of the first embodiment of the present technology.Therefore, the same reference numerals as those of the first embodimentof the present technology are given to portions common to the firstembodiment of the present technology, and the description thereof willbe omitted partially.

[Format Example of A-MPDU Frame]

FIG. 13 is a diagram illustrating a configuration example of a frameformat of the A-MPDU exchanged between information processing devicesincluded in a communication system 10 according to the second embodimentof the present technology.

The A-MPDU frame has the format of an aggregation frame generally usedfor a wireless LAN.

The A-MPDU is configured to include a plurality of A-MPDU subframes 320to 322. In each of the A-MPDU subframes 320 to 322, there are a MACheader and an FCS. For example, in the A-MPDU subframe 320, there is aMAC header 331 and an FCS 333. As described above, aggregation framesare a plurality of frames which are connected to be transmitted as oneframe. The subframe means one frame among a plurality of frames in aconnection frame (aggregation frame) in which the plurality of framesare connected.

Here, in the second embodiment of the present technology, as describedabove, the MAC payload (Frame Body 332) of the head subframe 320 of theA-MPDU frame is set to 0. That is, in the second embodiment of thepresent technology, a reception stop signal is set by adding onesubframe in which Frame Body 332 is set to 0 to the head of the A-MPDU.

When a transmission-side information processing device transmits areception stop signal, a new subframe is added to the head of the A-MPDUand the length of the MAC payload of the subframe is set to 0. Thus, thereception stop signal can be transmitted. That is, the control unit 130can use the head subframe of the aggregation frame as an index by whichreception is stopped.

For example, destinations of the individual subframes of the A-MPDU aredifferent in some cases. In this way, when the destinations of theindividual subframes of the A-MPDU are different, information (forexample, an identifier of a group) by which the destination can bedetermined to be the own information processing device may be used as adestination address stored in the head subframe. In this case, eachdevice of a transmission destination can determine whether a frame is aframe destined for the own information processing device based on theinformation (for example, an identifier of a group) stored in the headsubframe.

A process of determining whether to transmit a reception stop signal(step S720 illustrated in FIG. 6 ) and a transmission determinationprocess for the reception stop signal (step S740 illustrated in FIG. 6 )are the same as those of the first embodiment of the present technology.Therefore, the description thereof will be omitted here.

In this way, since transmission of the reception stop signal can berealized without changing all of the current IEEE 802.11 specification,it is possible to ensure backward compatibility.

[Operation Example of Reception Stop Determination Process]

FIG. 14 is a flowchart illustrating a reception stop determinationprocess (a processing procedure of step S750 illustrated in FIG. 7 ) ina frame reception process by the information processing device 200according to the second embodiment of the present technology. FIG. 14 isa drawing obtained by modifying a part of FIG. 11 . Therefore, the samereference numerals as those of FIG. 11 are given to portions common toFIG. 11 . The description thereof will be omitted partially.

Here, in the first embodiment of the present technology, the example inwhich the FCS for the MAC header is newly added and the FCS is confirmedhas been described. In the second embodiment of the present technology,however, an existing FCS is used and the FCS is confirmed (step S781).

Specifically, the control unit of the information processing device 200confirms the FCS of the head subframe of the A-MPDU frame (step S781).The FCS is, for example, the FCS 333 of the head subframe 320 of theA-MPDU frame illustrated in FIG. 13 .

Then, the control unit of the information processing device 200determines whether a checksum calculated from the head subframe of areceived A-MPDU frame is identical to a value of the FCS of the headsubframe (step S781). When the checksum is not identical to the value(step S781), the process proceeds to step S758. Conversely, when thechecksum is identical to the value (step S781), the process proceeds tostep S752.

[Operation Example of Frame Reception Stop Process]

FIG. 15 is a flowchart illustrating a frame reception stop process (aprocessing procedure of step S760 illustrated in FIG. 7 ) in the framereception process by the information processing device 200 according tothe second embodiment of the present technology. FIG. 15 is a drawingobtained by modifying a part of FIG. 12 . Therefore, the same referencenumerals as those of FIG. 12 are given to portions common to FIG. 12 .The description thereof will be omitted partially.

Here, in the first embodiment of the present technology, the example inwhich the FCS for the MAC header is newly added and the FCS is confirmedhas been described. In the second embodiment of the present technology,however, an existing FCS is used and the FCS is confirmed (step S791).

Specifically, the control unit of the information processing device 200confirms the FCS of the head subframe of the A-MPDU frame (step S791).The FCS is, for example, the FCS 333 of the head subframe 320 of theA-MPDU frame illustrated in FIG. 13 .

Then, the control unit of the information processing device 200determines whether a checksum calculated from the head subframe of areceived A-MPDU frame is identical to a value of the FCS of the headsubframe (step S791). When the checksum is not identical to the value(step S791), the process proceeds to step S771. Conversely, when thechecksum is identical to the value (step S791), the process proceeds tostep S762.

3. Third Embodiment

In a third embodiment of the present technology, an example in which areception stop signal is generated using SIG for IEEE 802.11ax (HE-SIG(High Efficiency SIGNAL)-A) will be described.

The configuration of an information processing device according to thethird embodiment of the present technology is substantially the same asthe information processing devices 100 and 200 to 204 illustrated inFIG. 1 and the like. Therefore, the same reference numerals as those ofthe first and second embodiments of the present technology are given toportions common to the first and second embodiments of the presenttechnology, and the description thereof will be omitted partially.

Some of the processes in the third embodiment of the present technologyare common to those of the first and second embodiments of the presenttechnology. Therefore, the same reference numerals as those of the firstand second embodiments of the present technology are given to portionscommon to the first and second embodiments of the present technology,and the description thereof will be omitted partially.

[Operation Example of Process to Determine Whether or not to TransmitReception Stop Signal]

FIG. 16 is a flowchart illustrating a process to determine whether ornot to transmit a reception stop signal (a processing procedure of stepS720 illustrated in FIG. 6 ) in a frame transmission process by theinformation processing device 100 according to the third embodiment ofthe present technology.

FIG. 16 illustrates an example of a case in which a transmission sideinformation processing device is the information processing device 100.FIG. 16 illustrates an example in which a determination process ofdetermining whether all of the other information processing devicesaround the information processing device 100 are information processingdevices corresponding to reception stop along with the processes of thefirst and second embodiments of the present technology. Here, theinformation processing device corresponding to reception stop is aninformation processing device capable of receiving a reception stopsignal.

The control unit 130 determines whether at least one of an AssociationRequest frame and a Probe Request frame is received (step S801).

When neither the Association Request frame nor Probe Request frame isreceived (step S801), monitoring is continued.

When at least one of the frames is received (step S801), the controlunit 130 determines whether the transmission source of the receivedframe is the information processing device corresponding to receptionstop (step S802).

When the transmission source of the received frame is the informationprocessing device corresponding to reception stop (step S802), thecontrol unit 130 determines whether the own information processingdevice (the information processing device 100) can transmit thereception stop signal (step S803).

When the own information processing device can transmit the receptionstop signal (step S803), the control unit 130 can determine whether allof the information processing devices (slave stations) connected to theown information processing device (the information processing device100) can transmit the reception stop signal (step S804).

When all of the information processing devices (slave stations)connected to the own information processing device can transmit thereception stop signal (step S804), the control unit 130 determineswhether other information processing devices (master stations) which canreceive the signal (step S805).

When there is no other information processing devices (master stations)which can receive the signal (step S805), the control unit 130determines that the reception stop signal can be transmitted (step S806)

When there are the other information processing devices (masterstations) which can receive the signal (step S805), the control unit 130determines whether all of the information processing devices (masterstations) can transmit the reception stop signal (step S807).

When all of the information processing devices (master stations) cantransmit the reception stop signal (step S807), the control unit 130determine that the reception stop signal can be transmitted (step S806).When all of the information processing devices (master stations) may nottransmit the reception stop signal (step S807), the control unit 130determines that the transmission of the reception stop signal is notpossible (step S808).

When the transmission source of the received frame is not theinformation processing device corresponding to reception stop (stepS802), the process proceeds to step S808. When the own informationprocessing device may not transmit the reception stop signal (stepS803), the process proceeds to step S808. When all of the informationprocessing devices (slave stations) connected to the own informationprocessing device may not transmit the reception stop signal (stepS804), the process proceeds to step S808.

Here, an information processing device which does not correspond to thereception stop function may not demodulate data even when theinformation processing device receives a frame including the receptionstop signal. Therefore, the reception stop signal is not transmitted toan information processing device which does not correspond to thereception stop function.

Here, for example, when an information processing device which does notcorrespond to the reception stop function receives transmission of thereception stop signal, the information processing device which does notcorrespond to the reception stop function ascertains that theinformation processing device receives a signal having an unclear formatand does not perform transmission during a period in which this signalis received. Even in this case, depending on a difference in the format,a problem in which an abnormal packet is sent to an upper layer does notoccur. Therefore, it is possible to ensure backward compatibility. Thatis, the third embodiment of the present technology is not limited to acase of the configuration of the information processing devicecorresponding to the reception stop function.

[Configuration Example of HE-SIG-A]

FIG. 17 is diagram illustrating a configuration example of HE-SIG (HighEfficiency SIGNAL)-A exchanged between information processing devicesincluded in the communication system 10 according to the thirdembodiment of the present technology.

FIG. 17 illustrates HE-SIG-A 341 as the SIG for IEEE 802.11ax.

In FIG. 17 illustrates a format example formed by a legacy shorttraining field (L-STF), a legacy long training field (L-LTF), legacySIGNAL (L-SIG), HE-SIG-A 341, a high efficiency short training field(HE-STF), a high efficiency long training field (HE-LTF), HE-SIG-B, andData of IEEE 802.11.

[Operation Example of Reception Stop Signal Transmission DeterminationProcess]

FIG. 18 is a flowchart illustrating a reception stop signal transmissiondetermination process (a processing procedure of step S740 illustratedin FIG. 6 ) in a frame transmission process by the informationprocessing device 100 according to the third embodiment of the presenttechnology.

The control unit 130 determines whether a transmission target frame istransmitted in a unicast manner or a multicast manner (step S811).

When the transmission target frame is transmitted in the unicast manneror the multicast manner (step S811), the control unit 130 sets areception stop signal by storing an RA in SIG for IEEE 802.11ax (stepS812). That is, the RA (the address of a transmission destination) isstored in SIG for IEEE 802.11ax.

Here, the unicast transmission or the multicast transmission is a schemeof designating a destination and performing transmission to aninformation processing device. Therefore, when the RA included in areceived frame is different, an information processing device receivingthe frame can determine that the frame is not destined for the owninformation processing device.

The SIG (HE-SIG-A 341 illustrated in FIG. 17 ) for IEEE 802.11ax is abit string which can be demodulated only by an information processingdevice corresponding to IEEE 802.11ax. Accordingly, by storinginformation serving as an index by which reception is stopped in SIG, aninformation processing device corresponding to IEEE 802.11ax can stopthe reception.

An information processing device which does not correspond to IEEE802.11ax may not read SIG for IEEE 802.11ax and does not performdemodulation because of an unclear format. Therefore, it is possible toensure backward compatibility.

When the transmission target frame is transmitted in a broadcast manner(step S811), the reception stop signal is set by storing the TA (theaddress of the own information processing device) in SIG for IEEE802.11ax (step S813).

Here, the broadcast transmission is a scheme used when all of theinformation processing devices capable of receiving frames are set asdestinations to perform transmission. When the TA is different from thatof the information processing device 100 to which the own informationprocessing device is connected, an information processing devicereceiving the frame can determine that the frame is not destined for theown information processing device.

In this way, the control unit 130 can set the reception stop signal bystoring information (the RA or the TA) serving as the index by whichreception is stopped in SIG for IEEE 802.11ax. Thus, the informationprocessing device receiving the frame can determine whether thereception of the frame is stopped based on the address stored in SIG forIEEE 802.11ax. That is, when the address stored in SIG is different fromthe address of the own information processing device or is differentfrom the address of the information processing device 100 to which theown information processing device is connected, the informationprocessing device can stop receiving the frame and discard the frame.

Here, for example, when a slave station performs unicast transmission toa master station, the slave station stores information regarding themaster station (the address of the master station) as the RA inHE-SIG-A. In this case, when another slave station connected to themaster station receives the signal, the other slave station may notdetermine whether the information regarding the master station stored inHE-SIG-A is the TA or the RA. Therefore, when the other slave stationconnected to the master station receives the signal, the other slavestation may continuously receive the signal despite the fact that thesignal is not a signal destined for the own information processingdevice. Accordingly, the slave station can correctly perform thedetermination by including an identifier for specifying which is storedbetween the RA and the TA. That is, the control unit 130 can include theidentifier for specifying which is stored between the RA and the TA inSIG for IEEE 802.11ax to transmit the identifier.

A reception-side device can acquire the information (the RA or the TA)serving as the index by which reception is stopped and the identifier(the identifier for specifying which is stored between the RA and theTA) included in SIG for IEEE 802.11ax in a received frame. Then, thereception-side device can correctly use the information (the RA or theTA) serving as the index by which reception is stopped, using theidentifier.

In this way, a value stored as the identifier may be the address, the RAor the TA or may be a compressed value which can be uniquely derivedfrom the address, the RA or the TA.

[Operation Example of Reception Stop Determination Process]

FIG. 19 is a flowchart illustrating a reception stop determinationprocess (a processing procedure of step S750 illustrated in FIG. 7 ) ina frame reception process by the information processing device 200according to the third embodiment of the present technology.

The control unit of the information processing device 200 confirms theaddress stored in SIG for IEEE 802.11ax in the received frame anddetermines whether an address for reception stop determination is stored(step S821).

When the address for the reception stop determination is not stored inSIG (step S821), the control unit of the information processing device200 performs control such that reception of the frame is continued (stepS823).

When the address for the reception stop determination is stored in SIG(step S821), the control unit of the information processing device 200determines whether the address is identical to the address of the owninformation processing device or the address of a group to which the owninformation processing device belongs (step S822).

When the address is identical to the address of the own informationprocessing device or the address of the group to which the owninformation processing device belongs (step S822), the control unit ofthe information processing device 200 performs control such that thereception of the frame is continued (step S823).

When the address is not identical to any of the address of the owninformation processing device and the address of the group to which theown information processing device belongs (step S822), the control unitof the information processing device 200 determines whether the addressis identical to the connection destination (step S824).

When the address is identical to the connection destination (step S824),the control unit of the information processing device 200 performscontrol such that the reception of the frame is continued (step S823).

When the address is not identical to the connection destination (stepS824), the control unit of the information processing device 200determines that the reception of the frame is stopped (step S825). Thus,the reception of the frame is stopped and the frame is discarded (stepS825).

[Operation Example of Frame Reception Stop Process]

FIG. 20 is a flowchart illustrating a frame reception stop process (aprocessing procedure of step S760 illustrated in FIG. 7 ) in a framereception process by the information processing device 200 according tothe third embodiment of the present technology.

First, the control unit of the information processing device 200calculates an end time of the received frame based on LENGTH and RATEstored in the PLCP header (step S831). Then, the control unit of theinformation processing device 200 sets transmission suppression so thattransmission is not performed for the calculated end time of thereceived frame (step S831).

By doing so, it is possible to reduce unnecessary transmission. Theinformation processing device 200 can reduce power and can also improvea system throughput by reducing collision occasions of frames.

Subsequently, the control unit of the information processing device 200determines whether the transmission suppression is being set (whether atime reaches the calculated end time of the received frame) (step S832).When the transmission suppression is not being set (when the timereaches the calculated end time of the received frame) (step S832), thecontrol unit of the information processing device 200 cancels thetransmission suppression (step S835).

When the period is during the transmission suppression (step S832), thecontrol unit of the information processing device 200 receives a newframe and determines whether the frame is a frame for which it isnecessary to transmit an acknowledgement (step S833).

When a new frame is received and the frame is a frame for which it isnecessary to transmit an acknowledgement (step S833), the control unitof the information processing device 200 transmits the acknowledgementto the transmission source of the frame (step S834) and the processreturns to step S832. Conversely, when the new frame is not received orthe received frame is a frame for which it is not necessary to transmitthe acknowledgement (step S833), the process returns to step S832.

In this way, in the first to third embodiments of the presenttechnology, it is possible to detect an error of a frame (for example, aMAC header) without changing the format of the frame. Thus, it ispossible to appropriately stop the reception of the frame which is beingreceived in consideration of backward compatibility, and thus improve areception opportunity of a frame.

In the first to third embodiments of the present technology, the casesin which a master station (the information processing device 100)transmits signals to slave stations (the information processing devices200 to 204) and the slave stations (the information processing devices200 to 204) receive the signals have been described as examples. Thefirst to third embodiments of the present technology can be similarlyapplied to a case in which slave stations (the information processingdevices 200 to 204) transmit signals to a master station (theinformation processing device 100) and the master station (theinformation processing device 100) receives the signals. The first tothird embodiments of the present technology can also be applied tocommunication between slave stations.

4. Application Examples

The technology according to the present disclosure can be applied tovarious products. For example, the information processing device 100, orinformation processing device 201 or 204 may be realized as mobileterminals such as smartphones, tablet personal computers (PCs), notebookPCs, portable game terminals, or digital cameras, fixed-type terminalssuch as television receivers, printers, digital scanners, or networkstorages, or car-mounted terminals such as car navigation apparatuses.Further, the information processing device 100, or informationprocessing device 201 or 204 may be realized as terminals (also referredto as machine type communication (MTC) terminals) which perform machineto machine (M2M) communication, such as smart meters, vending machine,remote monitoring apparatuses and point of sale (POS) terminals.Furthermore, the information processing device 100, or informationprocessing device 201 or 204 may be wireless communication modulesmounted in such terminals (for example, integrated circuit modulesconfigured in one die).

For example, the information processing device 100 may be realized as awireless LAN access point (which is also referred to as a wireless basestation) that has no router function or has a router function. Theinformation processing device 100 may be realized as a mobile wirelessLAN router. Furthermore, the information processing device 100 may bewireless communication modules mounted in such devices (for example,integrated circuit modules configured in one die).

4-1. First Application Example

FIG. 21 is a block diagram showing an example of a schematicconfiguration of a smartphone 900 to which the technology of the presentdisclosure can be applied. The smartphone 900 includes a processor 901,a memory 902, a storage 903, an externally connected interface 904, acamera 906, a sensor 907, a microphone 908, a input device 909, adisplay device 910, a speaker 911, a wireless communication interface913, an antenna switch 914, an antenna 915, a bus 917, a battery 918,and an auxiliary controller 919.

The processor 901 may be, for example, a central processing unit (CPU)or a system on chip (SoC), and controls functions of an applicationlayer and other layers of the smartphone 900. The memory 902 includes arandom access memory (RAM) and a read only memory (ROM), and storesprograms executed by the processor 901 and data. The storage 903 caninclude a storage medium such as a semiconductor memory or a hard disk.The externally connected interface 904 is an interface for connecting anexternally attached device such as a memory card or a universal serialbus (USB) device to the smartphone 900.

The camera 906 has an image sensor, for example, a charge coupled device(CCD) or a complementary metal oxide semiconductor (CMOS) to generatecaptured images. The sensor 907 can include a sensor group including,for example, a positioning sensor, a gyro sensor, a geomagnetic sensor,an acceleration sensor, and the like. The microphone 908 converts soundsinput to the smartphone 900 into audio signals. The input device 909includes, for example, a touch sensor that detects touches on a screenof the display device 910, a key pad, a keyboard, buttons, switches, andthe like to receive manipulations or information inputs from a user. Thedisplay device 910 has a screen such as a liquid crystal display (LCD),or an organic light emitting diode (OLED) display to display outputimages of the smartphone 900. The speaker 911 converts audio signalsoutput from the smartphone 900 into sounds.

The wireless communication interface 913 supports one or more wirelessLAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad to executewireless LAN communication. The wireless communication interface 913 cancommunicate with another apparatus via a wireless LAN access point inthe infrastructure mode. In addition, the wireless communicationinterface 913 can directly communicate with another apparatus in adirect communication mode, such as an ad hoc mode, Wi-Fi Direct, or thelike. In Wi-Fi Direct, one of two terminals operates as an access pointunlike in an ad hoc mode, but communication is performed directlybetween the terminals. The wireless communication interface 913 cantypically have a baseband processor, an radio frequency (RF) circuit, apower amplifier, and the like. The wireless communication interface 913may be a single-chip module on which a memory that stores acommunication control program, a processor that executes the program,and a relevant circuit are integrated. The wireless communicationinterface 913 may support another kind of wireless communication schemesuch as a short-range wireless communication scheme, a proximitywireless communication scheme, or the cellular communication scheme inaddition to the wireless LAN scheme. The antenna switch 914 switches aconnection destination of the antenna 915 for a plurality of circuits(for example, a circuit for another wireless communication scheme)included in the wireless communication interface 913. The antenna 915has a single or a plurality of antenna elements (for example, aplurality of antenna elements included in a MIMO antenna) and is usedfor transmission and reception of wireless signals from the wirelesscommunication interface 913.

Note that the smartphone 900 may include a plurality of antennas (forexample, antennas for a wireless LAN or antennas for a proximitywireless communication scheme, or the like), without being limited tothe example of FIG. 21 . In this case, the antenna switch 914 may beomitted from the configuration of the smartphone 900.

The bus 917 connects the processor 901, the memory 902, the storage 903,the externally connected interface 904, the camera 906, the sensor 907,the microphone 908, the input device 909, the display device 910, thespeaker 911, the wireless communication interface 913, and the auxiliarycontroller 919 to one another. The battery 918 supplies electric powerto each of the blocks of the smartphone 900 shown in FIG. 21 via powersupply lines partially indicated by dashed lines in the drawing. Theauxiliary controller 919 causes, for example, required minimum functionsof the smartphone 900 to be operated in a sleep mode.

The communication unit 120 and the control unit 130 described withreference to FIG. 2 in the smartphone 900 shown in FIG. 28 may bemounted on the wireless communication interface 913. At least some ofthe functions may be mounted on the processor 901 or the auxiliarycontroller 919. For example, it is possible to reduce power consumptionof the battery 918 using efficiently radio resources through grouping.

The smartphone 900 may operate as a wireless access point (software AP)when the processor 901 performs an access point function at anapplication level. The wireless communication interface 913 may have thewireless access point function.

4-2. Second Application Example

FIG. 22 is a block diagram showing an example of a schematicconfiguration of a car navigation apparatus 920 to which the technologyof the present disclosure can be applied. The car navigation apparatus920 includes a processor 921, a memory 922, a global positioning system(GPS) module 924, a sensor 925, a data interface 926, a content player927, a storage medium interface 928, an input device 929, a displaydevice 930, a speaker 931, a wireless communication interface 933, anantenna switch 934, an antenna 935, and a battery 938.

The processor 921 may be, for example, a CPU or an SoC controlling anavigation function and other functions of the car navigation apparatus920. The memory 922 includes a RAM and a ROM storing programs executedby the processor 921 and data.

The GPS module 924 measures a position of the car navigation apparatus920 (for example, latitude, longitude, and altitude) using GPS signalsreceived from a GPS satellite. The sensor 925 can include a sensor groupincluding, for example, a gyro sensor, a geomagnetic sensor, abarometric sensor, and the like. The data interface 926 is connected toan in-vehicle network 941 via, for example, a terminal that is notillustrated to acquire data generated on the vehicle side such as carspeed data.

The content player 927 reproduces content stored in a storage medium(for example, a CD or a DVD) inserted into the storage medium interface928. The input device 929 includes, for example, a touch sensor thatdetects touches on a screen of the display device 930, buttons,switches, and the like to receive manipulations or information inputsfrom a user. The display device 930 has a screen such as an LCD or anOLED display to display images of the navigation function or reproducedcontent. The speaker 931 outputs sounds of the navigation function orreproduced content.

The wireless communication interface 933 supports one or more wirelessLAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad to executewireless LAN communication. The wireless communication interface 933 cancommunicate with another apparatus via a wireless LAN access point inthe infrastructure mode. In addition, the wireless communicationinterface 933 can directly communicate with another apparatus in adirect communication mode, such as an ad hoc mode, Wi-Fi Direct, or thelike. The wireless communication interface 933 can typically have abaseband processor, an RF circuit, a power amplifier, and the like. Thewireless communication interface 933 may be a single-chip module onwhich a memory that stores a communication control program, a processorthat executes the program, and a relevant circuit are integrated. Thewireless communication interface 933 may support another kind ofwireless communication scheme such as a short-range wirelesscommunication scheme, a proximity wireless communication scheme, or thecellular communication scheme in addition to the wireless LAN scheme.The antenna switch 934 switches a connection destination of the antenna935 for a plurality of circuits included in the wireless communicationinterface 933. The antenna 935 has a single or a plurality of antennaelements and is used for transmission and reception of wireless signalsfrom the wireless communication interface 933.

Note that the car navigation apparatus 920 may include a plurality ofantennas, without being limited to the example of FIG. 22 . In thiscase, the antenna switch 934 may be omitted from the configuration ofthe car navigation apparatus 920.

The battery 938 supplies electric power to each of the blocks of the carnavigation apparatus 920 shown in FIG. 22 via power supply linespartially indicated by dashed lines in the drawing. In addition, thebattery 938 accumulates electric power supplied from the vehicle.

The communication unit 120 and the control unit 130 described withreference to FIG. 2 in the car navigation apparatus 920 shown in FIG. 22may be mounted on the wireless communication interface 933. At leastsome of the functions may be mounted on the processor 921.

The wireless communication interface 933 may operate as theabove-described information processing device 100 or may providewireless connection to a terminal carried by a user getting in avehicle.

The technology of the present disclosure may be realized as anin-vehicle system (or a vehicle) 940 including one or more blocks of theabove-described car navigation apparatus 920, the in-vehicle network941, and a vehicle-side module 942. The vehicle-side module 942generates vehicle-side data such as a vehicle speed, the number ofengine rotations, or failure information and outputs the generated datato the in-vehicle network 941.

4-3. Third Application Example

FIG. 23 is a block diagram showing an example of a schematicconfiguration of a wireless access point 950 to which the technology ofthe present disclosure can be applied. The wireless access point 950includes a controller 951, a memory 952, an input device 954, a displaydevice 955, a network interface 957, a wireless communication interface963, an antenna switch 964, and an antenna 965.

The controller 951 may be, for example, a CPU or a digital signalprocessor (DSP) and operates various functions (for example, accessrestriction, routing, encryption, firewall, and log management) of theInternet Protocol (IP) layer and higher layers of the wireless accesspoint 950. The memory 952 includes a RAM and a ROM and stores a programto be executed by the controller 951 and various kinds of control data(for example, a terminal list, a routing table, an encryption key,security setting, and a log).

The input device 954 includes, for example, buttons or switches andreceives manipulations from a user. The display device 955 includes anLED lamp or the like and displays operation status of the wirelessaccess point 950.

The network interface 957 is a wired communication interface thatconnects the wireless access point 950 to a wired communication network958. The network interface 957 may include a plurality of connectionterminals. The wired communication network 958 may be a LAN such asEthernet (registered trademark) or a wide area network (WAN).

The wireless communication interface 963 supports one or more wireless

LAN standards of IEEE 802.11a, 11b, 11g, 11n, 11ac, and 11ad to providea wireless connection to a terminal located nearby as an access point.The wireless communication interface 963 can typically have a basebandprocessor, an RF circuit, a power amplifier, and the like. The wirelesscommunication interface 963 may be a single-chip module on which amemory that stores a communication control program, a processor thatexecutes the program, and a relevant circuit are integrated. The antennaswitch 964 switches a connection destination of the antenna 965 for aplurality of circuits included in the wireless communication interface963. The antenna 965 has a single antenna element or a plurality ofantenna elements and is used for transmission and reception of wirelesssignals from the wireless communication interface 963.

In the wireless access point 950 shown in FIG. 23 , the control unit 130shown in FIG. 2 may be mounted on the wireless communication interface963. At least some of the functions may be implemented in the controller951.

The above-described embodiments are examples for embodying the presenttechnology and have correspondence relations with factors in embodimentsand specific inventive factors in the claims. Similarly, specificinventive factors in the claims and factors in embodiments of thepresent technology to which the same names as the specific inventivefactors are given have correspondence relations. However, the presenttechnology is not limited to the embodiments, but may be realized invarious modification forms of the embodiments within the scope notdeparting from the gist of the present technology.

The processing sequences that are described in the embodiments describedabove may be handled as a method having a series of sequences or may behandled as a program for causing a computer to execute the series ofsequences and recording medium storing the program. As the recordingmedium, a hard disk, a CD (Compact Disc), an MD (MiniDisc), and a DVD(Digital Versatile Disk), a memory card, and a Blu-ray disc (registeredtrademark) can be used.

In addition, the effects described in the present specification are notlimiting but are merely examples, and there may be additional effects.

Additionally, the present technology may also be configured as below.

(1)

An information processing device including:

a control unit configured to perform control in a manner that a signalhaving backward compatibility and serving as an index by which anotherinformation processing device receiving a frame stops the reception ofthe frame is transmitted to the other information processing device.

(2)

The information processing device according to (1),

wherein the control unit uses, as the index, information which is basedon a calculation result obtained using a MAC header.

(3)

The information processing device according to (2),

wherein the control unit stores the information which is based on thecalculation result in a header of a physical layer in the frame and usesthe information as the signal.

(4)

The information processing device according to (1),

wherein the control unit uses, as the index, one frame among a pluralityof frames in a connection frame in which the plurality of frames areconnected.

(5)

The information processing device according to (1),

wherein the control unit stores, as an index, an address of atransmission source or an address of a transmission destination asinformation which is the index, in a header of a physical layer in theframe.

(6)

The information processing device according to any of (1) to (5),

wherein the control unit determines whether to transmit the signal basedon at least one of information from a base station, information from awireless slave station, a length of a transmission target frame, andwhether to perform transmission in a bundle of a plurality offrequencies.

(7)

An information processing device including:

a control unit configured to perform control in a manner that receptionof a frame transmitted from another information processing device isstopped based on an index by which reception of the frame is stopped andwhich is specified by a signal having backward compatibility when theframe is received.

(8)

The information processing device according to (7), wherein

the index includes an FCS of a MAC header included in the signal, and

the control unit determines whether there is an error in data of the MACheader based on a comparison result between the FCS and a checksumcalculated based on the MAC header.

(9)

The information processing device according to (8),

wherein the index is stored in one frame among a plurality of frames ina connection frame in which the plurality of frames are connected.

(10)

The information processing device according to (8),

wherein the index is stored in a header of a physical layer.

(11)

The information processing device according to any of (7) to (11),

wherein the control unit determines whether there is an error in data ofa MAC header of the frame based on the index and performs control in amanner that the reception of the frame is stopped when there is theerror in the data of the MAC header.

(12)

The information processing device according to any of (7) to (11),

wherein, when there is no error in data of a MAC header of the frame,the control unit determines that the reception of the frame is stoppedin a case in which the frame is transmitted in a unicast manner and atransmission destination of the frame is not destined for the owninformation processing device and a case in which the frame istransmitted in a multicast manner and the transmission destination ofthe frame is not destined for a multicast group to which the owninformation processing device belongs.

(13)

The information processing device according to any of (7) to (11),

wherein, when there is no error in data of a MAC header of the frame,the control unit determines that the reception of the frame is stoppedin a case in which the frame is transmitted in a broadcast manner and atransmission destination of the frame is not an information processingdevice to which the own information processing device is connected.

(14)

The information processing device according to any of (7) to (11),

wherein, when there is no error in data of a MAC header of the frame,the control unit performs control in a manner that a carrier sense levelis changed in a case in which a transmission destination or atransmission source of the frame of which the reception is stopped isnot an information processing device to which the own informationprocessing device is connected.

(15)

The information processing device according to any of (7) to (14),

wherein the control unit performs control in a manner that transmissionsuppression is set until a reception end timing of the frame of whichthe reception is stopped.

(16)

The information processing device according to (15),

wherein, when the transmission suppression is set, the control unitperforms control in a manner that an acknowledgement is transmitted in acase in which a frame destined for the own information processing deviceis received, at least one frame among frames destined for the owninformation processing device is correctly receivable, and it isnecessary to transmit the acknowledgement to a transmission source ofthe frame destined for the own information processing device.

(17)

The information processing device according to (15) or (16),

wherein, when there is no error in data of a MAC header of the frame,the control unit performs control in a manner that the transmissionsuppression is set during a transmission suppression period decidedbased on information stored in the frame of which the reception isstopped.

(18)

A communication system including:

a first information processing device configured to perform control in amanner that a signal having backward compatibility and serving as anindex by which a second information processing device receiving a framestops the reception of the frame is transmitted to the secondinformation processing device; and

the second information processing device configured to perform controlin a manner that the reception of the frame is stopped based on thesignal when the frame transmitted from the first information processingdevice is received.

(19)

An information processing method of transmitting a signal havingbackward compatibility and serving as an index by which anotherinformation processing device receiving a frame stops the reception ofthe frame, to the other information processing device.

(20)

An information processing method of stopping reception of a frametransmitted from another information processing device based on an indexby which reception of the frame is stopped and which is specified by asignal having backward compatibility when the frame is received.

REFERENCE SIGNS LIST

-   -   10 communication system    -   100, 200 to 204 information processing device    -   110 antenna    -   120 communication unit    -   130 control unit    -   140 storage unit    -   900 smartphone    -   901 processor    -   902 memory    -   903 storage    -   904 externally connected interface    -   906 camera    -   907 sensor    -   908 microphone    -   909 input device    -   910 display device    -   911 speaker    -   913 wireless communication interface    -   914 antenna switch    -   915 antenna    -   917 bus    -   918 battery    -   919 auxiliary controller    -   920 car navigation apparatus    -   921 processor    -   922 memory    -   924 GPS module    -   925 sensor    -   926 data interface    -   927 content player    -   928 storage medium interface    -   929 input device    -   930 display device    -   931 speaker    -   933 wireless communication interface    -   934 antenna switch    -   935 antenna    -   938 battery    -   941 in-vehicle network    -   942 vehicle-side module    -   950 wireless access point    -   951 controller    -   952 memory    -   954 input device    -   955 display device    -   957 network interface    -   958 wired communication network    -   963 wireless communication interface    -   964 antenna switch    -   965 antenna

The invention claimed is:
 1. An information processing device,comprising: processing circuitry configured to perform control toreceive an aggregated media access control protocol data unit (A-MPDU)subframe from another information processing device, the A-MPDU subframehaving backward compatibility and including address fields; upondetecting a frame check sequence (FCS) up to a media access control(MAC) header of the A-MPDU subframe, in a case where there is no errorin data of the MAC header of the A-MPDU subframe, perform control tostop reception of an A-MPDU including the A-MPDU subframe based on firstinformation of the address fields, which are included in the MAC headerof the A-MPDU subframe; and raise a carrier sense level for channelaccess in a case where second information of the address fields of theA-MPDU of which the reception is stopped is not for an informationprocessing apparatus to which the information processing device isconnected.
 2. The information processing device according to the claim1, wherein the processing circuitry is configured to perform control: tochange the carrier sense level from a default value to a first valuewhich is higher than the default value, in a case where the secondinformation of the address fields of the A-MPDU of which the receptionis stopped is not for the information processing apparatus to which theinformation processing device is connected.
 3. The informationprocessing device according to the claim 2, wherein the processingcircuitry is configured to perform control: after changing the carriersense level to the first value, to determine whether or not theprocessing circuitry is during a change period of the carrier senselevel, and to return the carrier sense level to the default value basedon a determination that the processing circuitry is not during thechange period.
 4. The information processing device according to theclaim 3, wherein the processing circuitry is configured to performcontrol: based on the determination that the processing circuitry isduring the change period and a frame for which an acknowledgement isrequired is received during the change period, to transmit theacknowledgement to a transmission source of the frame.
 5. Theinformation processing device according to the claim 2, wherein thefirst value is −62 dBm, and the default value is −82 dBm.
 6. Theinformation processing device according to the claim 1, wherein, thefirst information is different from the second information.
 7. Theinformation processing device according to the claim 1, wherein, thefirst information is the same as the second information.
 8. Theinformation processing device according to the claim 1, furthercomprising: a processor; an input device; a display device; and a firstantenna element.
 9. The information processing device according to theclaim 8, further comprising: a speaker; an external connection interfacefor coupling a memory card or a universal serial bus (USB) device to theinformation processing device; a second antenna elements which isconstituting a MIMO antenna with the first antenna; and a power supplyunit which supplies power to the processing circuitry, the processor,the external connection interface, the input device, the display device,the speaker, the first and second antenna elements.
 10. The informationprocessing device according to the claim 8, further comprising: acontent payer reproducing a content stored in an external storage mediumand accessed through a storage medium interface.
 11. The informationprocessing device according to the claim 8, wherein, the display deviceis an LED lump which displays operation status of the informationprocessing device.
 12. An information processing method, comprising:performing control to receive an aggregated media access controlprotocol data unit (A-MPDU) subframe, by processing circuitry of aninformation processing device, from another information processingdevice, the A-MPDU subframe having backward compatibility and includingaddress fields; upon detecting a frame check sequence (FCS) up to amedia access control (MAC) header of the A-MPDU subframe, in a casewhere there is no error in data of the MAC header of the A-MPDUsubframe, performing control to stop reception of an A-MPDU includingthe A-MPDU subframe based on first information of the address fields,which are included in the MAC header of the A-MPDU subframe: andraising, by the processing circuitry, a carrier sense level for channelaccess in a case where second information of the address fields of theA-MPDU of which the reception is stopped is not for an informationprocessing apparatus to which the information processing device isconnected.
 13. The information processing method according to the claim12, further comprising: performing control to change the carrier senselevel from a default value to a first value which is higher than thedefault value, in a case where the second information of the addressfields of the A-MPDU of which the reception is stopped is not for theinformation processing apparatus to which the information processingdevice is connected.
 14. The information processing method according tothe claim 13, further comprising: after changing the carrier sense levelto the first value, performing control to determine whether or not theprocessing circuitry is during a change period of the carrier senselevel; and performing control to return the carrier sense level to thedefault value based on a determination that the processing circuitry isnot during the change period.
 15. The information processing methodaccording to the claim 14, further comprising: based on thedetermination that the processing circuitry is during the change periodand a frame for which an acknowledgement is required is received duringthe change period, performing control to transmit the acknowledgement toa transmission source of the frame.
 16. The information processingmethod according to the claim 14, wherein the first value is −62 dBm,and the default value is −82 dBm.
 17. The information processing methodaccording to the claim 12, wherein, the first information is differentfrom the second information.
 18. The information processing methodaccording to the claim 12, wherein, the first information is the same asthe second information.
 19. A non-transitory computer readable mediumincluding executable instructions, which when executed by a computercause the computer to execute an information processing method, themethod comprising: performing control to receive an aggregated mediaaccess control protocol data unit (A-MPDU) subframe, by processingcircuitry of an information processing device, from another informationprocessing device, the A-MPDU subframe having backward compatibility andincluding address fields; upon detecting a frame check sequence (FCS) upto a media access control (MAC) header of the A-MPDU subframe, in a casewhere there is no error in data of the MAC header of the A-MPDUsubframe, performing control to stop reception of an A-MPDU includingthe A-MPDU subframe based on first information of the address fields,which are included in the MAC header of the A-MPDU subframe; andraising, by the processing circuitry, a carrier sense level for channelaccess in a case where second information of the address fields of theA-MPDU of which the reception is stopped is not for an informationprocessing apparatus to which the information processing device isconnected.
 20. The non-transitory computer readable medium according tothe claim 3, further comprising: performing control to change thecarrier sense level from a default value to a first value which ishigher than the default value, in a case where the second information ofthe address fields of the A-MPDU of which the reception is stopped isnot for the information processing apparatus to which the informationprocessing device is connected.